Knee: distal femur (supracondylar) fractures

Distal femur fractures are severe knee injuries that threaten the viability of the limb.

When the fractures are not displaced, nonsurgical treatment may be an option.

Most supracondylar femur fractures are treated with surgery in order to decrease the odds of deformity and stiffness.

How is the surgery done?

Most distal femur fractures are treated by plating the fracture laterally. The approach is safe, fairly routine, but the incision can be very large.

The broken fragments of bone are realigned by placing traction on the foot, and by using various clamps and temporary wires. The plate is then placed adjacent to the fracture, and screws are placed above and below the fracture.

For certain fracture patterns, it may be possible to reduce and stabilize the condyles with several screws, and then to stabilize the reconstructed condyle block to the shaft with an intramedullary nail.

What is the recovery like?

  1. The surgery marks the beginning of the healing, not the end. In the best case scenario, this type of fracture may preliminarily heal in about 2 months. Typically the time required is longer. Full healing takes 1 year.
  2. The plate and screws are not able to support anybody's weight and may fail or break or loosen. It is important to remember that it is always a race between the bone healing and the hardware failing.
  3. Patient must protect the injured knee for a minimum of 2 months. Crutches, walker, or wheelchair may be necessary in order to avoid bearing weight while the fracture heals.
  4. Physical therapy with passive and active-assisted range of motion is necessary immediately, in order to avoid excessive stiffness.
  5. Staples are removed 2 weeks after surgery. Follow up xrays are done in 2 weeks, 4 weeks, 8 weeks, 4 months, and 1 year.

What are the risks of surgery?

  1. As with any other surgery, there is a risk of sudden death, heart attack, stroke, etc.
  2. Risk of infection: the risk of infection is approximately 1%.
  3. As with other fracture surgeries, there is a risk of malunion, nonunion, hardware breakage, and therefore possible repeat surgery
  4. Blood clots, DVT, and PE deserve a special mention.
  5. The knee is also prone to stiffness after this type of injury.

Case study

This was an intraarticular OTA C3 closed fracture. The entire articular surface is involved. Notice the presence of three condylar lines in the lateral view. Since a knee only has two condyles, this finding indicates a split in the sagital plane of one of them.

The extent of comminution can best be appreciated by looking at the CT slices. The CT confirms the sagital plane fracture of one of the condyles (the medial condyle in the left of the axial section).

Standard lateral approach was carried out, anterior to the intermuscular septum, followed by painstaking reconstruction of the distal femoral articular surface. The condylar reconstructed fragment was held together intraoperatively with multiple K-wires, which were then removed after insertion of the permanent implants.

These are xrays done after the surgery, with alignment restored.

Physical therapy was immediate and vigorous, albeit without allowing weight bearing.

Following are xrays done at 3 months after surgery. There is some loss of alignment, but the patient was pain free, bearing weight, and motion of the knee was fluid, despite his preexisting arthritic disease.

Additional degenerative changes are possible, and his arthritis may worsen in the future. A knee replacement may be necessary. However goals of treatment of the fracture have been achieved: namely a pain-free, stable knee with good alignment.